Interesting effort to try to distinguish an amply-supported (and not terribly novel) argument.
The authority cited by the professors says this: before FISA, there would be no doubt that the President was correct; but once Congress enacted FISA (a valid exercise of its Article I powers, it would seem), the President had to play by that rule -- that is, the President had to seek warrants to conduct domestic searches, even for the purposes of obtaining foreign intelligence, more than 15 days after a declaration of war. The only way the White House can get around that argument is to contend that the AUMF repealed some parts of FISA, but implied repeals aren't favored and there is no suggestion anywhere in the AUMF that Congress had any intention to repeal FISA.
The cases you cite, other than In re Sealed Case and Hamzi all pre-date FISA, making those decisions arguably correct in their pre-FISA context. The pre-FISA holdings appear to be directly contradicted (and apparently, intentionally so) by the enactment of FISA.
The FISC's decision in Sealed Case is far from authoritative, though I'll agree it's the only law on the issue. Nevertheless, it's the law in the same sense that the determination of a Tax Court or a Magistrate Judge is law.